1. Field of the Invention
This invention relates to aboveground fuel and fueling systems, such as those that are manufactured by U-Fuel, Inc. of Eau Claire, Wis. Specifically, the invention pertains to processes and systems for testing aboveground fuel and fueling systems for resistance against fire-related emergencies.
2. Description of the Related Technology
Nearly all modern airports and marinas have facilities of some type for refueling. The most prevalent type of aircraft refueling facility includes a belowground storage tank and an aboveground pumping module that is operated by an attendant, much in the manner of commercial service stations for automobiles.
One significant disadvantage of such in-ground refueling stations is the time and labor involved in preparing for and constructing such a facility. Some factors which contribute to the expense of constructing a belowground facility include the need for construction permits, subcontractors, excavation and the time and planning involved in locating a permanent site for the facility. Once installed, such facilities can not practically be moved to different locations at the airport, to other airports, or be sold.
In recent years, some aboveground refueling facilities have become commercially available. This development in the field has been pioneered by U-Fuel, Inc. of Eau Claire, Wis. Examples of the new aboveground technology include the systems that are described in the following U.S. Patents:
5,898,376 Modular overfill alarm assembly for vented storage tanks 5,723,842 Above-ground fire-resistant storage tank system and fabrication method 5,562,162 Portable fueling facility 5,305,926 Portable fueling facility having fire-retardant material 4,988,020 Portable fueling facility
Another concern that is often expressed by regulatory authorities and the owners of aboveground fuel storage facilities is the possibility of catastrophic fire or explosion if surrounding objects catch on fire. One standard that has been promulgated for such units holds that risk is sufficiently minimized when a tank can withstand a 2000.degree. F. environment for two hours. This standard is codified in Underwriters Laboratories test procedure 2085.
Unfortunately, it is difficult to perform a test as rigorous as that set forth above on an aboveground fueling system that simulates real world conditions. Because of the enormous combustion power of fuels such as propane, gasoline and jet fuel in quantities that would be sufficient to fill a typical aboveground fuel storage unit, the prevalent attitude in the industry prior to this invention was that it is too dangerous to subject such a unit when filled with fuel to a test fire under any circumstances. Instead, testing of such equipment has been done on empty tanks, or prototypes in ovens or open fires.
In addition, the previous testing methods were felt inadequate by some because they failed to take into account such factors as wind, which during a fire can cause sharp temperature gradients on the tank surface, thereby generating uneven strain that could potentially result in a breach in the tank.
It is clear there has existed a long and unfilled need in the prior art for a process for testing aboveground fuel tanks and fueling systems for their ability to withstand fire-related emergencies that more accurately simulates conditions of a likely fire-related emergency than tests that have heretofore been practiced and proposed.